How to Choose the Right Pipe Insulation
How to Choose the Right Pipe Insulation
A Complete Buyer's Guide for HVAC, Refrigeration & Plumbing Applications
Choosing the right pipe insulation is critical for energy efficiency, condensation control, and system longevity. This guide walks you through the key factors to consider when selecting insulation for any application.
🎯 The 5 Key Questions
Before selecting insulation, answer these five questions:
1. What is the pipe temperature?
- Cold (below ambient): Chilled water, refrigeration → Use closed-cell elastomeric
- Warm (40-80°C): HVAC heating, domestic hot water → Use elastomeric or PE
- Hot (80-105°C): High-temp HVAC → Use elastomeric (ST/Solar HT)
- Very hot (>105°C): Steam, industrial heating → Use mineral wool
2. Is condensation a risk?
If the pipe is below ambient temperature (chilled water, refrigeration, cold water), you MUST use closed-cell insulation with a built-in vapour barrier.
Best choice: K-FLEX ST or SK elastomeric insulation
3. What are the fire safety requirements?
- Standard applications: Class O/Class 1 (elastomeric) is acceptable
- Fire-critical areas: Plant rooms, commercial risers → Use non-combustible mineral wool (A1/A2 rating)
4. Is the pipe indoors or outdoors?
- Indoors: Standard elastomeric (ST/SK) or mineral wool
- Outdoors: Use UV-resistant Solar HT or protect with cladding
5. What thickness do you need?
Thickness depends on pipe temperature and ambient conditions:
- Domestic hot/cold water: 13 mm
- HVAC heating: 13-19 mm
- Chilled water: 19-25 mm
- Refrigeration: 19-32 mm
📋 Material Selection Guide
🔵 Elastomeric (K-FLEX ST/SK/PE)
Best for: Chilled water, refrigeration, HVAC, heat pumps, domestic plumbing
Temperature range: -50°C to +105°C (Solar HT: +150°C)
Key benefits:
- ✅ Built-in vapour barrier (no wrapping needed)
- ✅ Excellent condensation control
- ✅ Fast, flexible installation
- ✅ Self-seal options available (SK range)
Learn more about elastomeric insulation →
🔴 Mineral Wool (K-Rock)
Best for: High-temperature steam, fire-critical plant rooms, commercial risers
Temperature range: -40°C to +250°C
Key benefits:
- ✅ Non-combustible (A1/A2 fire rating)
- ✅ High-temperature performance
- ✅ Excellent thermal efficiency
Learn more about mineral wool insulation →
🟢 Polyethylene (K-FLEX PE)
Best for: Domestic hot & cold water, light commercial applications
Temperature range: -40°C to +95°C
Key benefits:
- ✅ Lightweight and economical
- ✅ Easy DIY installation
- ✅ Good for domestic plumbing
🛠Installation Considerations
Fast Installation?
Choose K-FLEX SK (Self-Seal) for the fastest installation — no adhesive needed, just peel and stick.
Complex Pipework?
Elastomeric tubes are flexible and easy to fit around bends, elbows, and tees. Mineral wool requires pre-formed sections.
Outdoor Installation?
Use K-FLEX Solar HT for UV resistance, or protect standard insulation with aluminium or PVC cladding.
✅ Quick Decision Matrix
| Application | Recommended Material | Thickness |
|---|---|---|
| Domestic Hot Water | PE or Elastomeric | 13 mm |
| Domestic Cold Water | Elastomeric (closed-cell) | 13 mm |
| HVAC Heating | Elastomeric or Mineral Wool | 13-19 mm |
| Chilled Water | Elastomeric (ST/SK) | 19-25 mm |
| Refrigeration | Elastomeric (ST/SK) | 19-32 mm |
| Heat Pump Lines | Elastomeric | 13-19 mm |
| High-Temp Steam | Mineral Wool (K-Rock) | 25-50 mm |
📚 Related Guides
- Insulation Thickness Selection Guide
- Elastomeric vs Mineral Wool — Which Is Best?
- Pipe Bore Size Chart
- Dew Point & Condensation Explained
- Back to Knowledge Centre
🛒 Shop by Application
Still not sure? Contact our technical team for project-specific advice.